Patrick Maier Compositional Circular Assume-Guarantee Rules Cannot Be Sound and Complete ABSTRACT: Circular assume-guarantee reasoning is used for the compositional verification of concurrent systems. Its soundness has been studied in depth, perhaps because circularity makes it anything but obvious. In this paper, we investigate completeness. We show that compositional circular assume-guarantee rules cannot be both sound and complete. KEYWORDS: compositional verification, assume-guarantee reasoning, completeness.